1. Field of the Invention
The present invention relates to a power semiconductor device for driving a power device, and more particularly, to a power semiconductor device such as a high voltage integrated circuit (HVIC) that includes a bootstrap circuit including a charge enable unit and a high voltage cut-off unit.
2. Description of the Related Art
A high voltage integrated circuit (HVIC), in which one or more high voltage transistors are arranged on a single chip together with low voltage circuits, are commonly used in a power control system such as a switching power supply or a motor driver. In general, an HVIC includes a high voltage unit and a low voltage unit. The low voltage unit operates in a fixed reference voltage environment such as a ground voltage. However, the high voltage unit should operate in a reference voltage environment that varies to a high voltage or a ground voltage according to a pulse width modulation (PWM) signal.
In order to stably operate the high voltage unit in a variable reference voltage environment, a bootstrap circuit is used in addition to a HVIC. The bootstrap circuit includes a capacitor connected in parallel to the high voltage unit at a driving power source terminal of the high voltage unit. The bootstrap circuit also includes a diode. The diode may open the bootstrap circuit when a PWM signal is at logic high and may supply a current to a capacitor by providing a current path when the PWM signal is at logic low.
A user should connect a bootstrap circuit to an HVIC in order to operate the HVIC. Also, due to the bootstrap circuit, the size of a whole module increases.